Process of treating oils



A ril 18, 1933. A. A. WELLS PROCESS OF TREATING OILS Filed Nov. 22, 1929r INVE'N'II'OR ATTORNEY Patented Apr. 18, 1933 UNITED STATES ALFRED A.

PATENT? OFFICE WELLS, 0F ROSELLE PARK, NEW JERSEY, ASSIGNOR TO STANDARDOIL DEVELOPMENT COMPANY, A. CORPORATION OF DELAWARE rnocnss or TREATINGOILS Application filed November 22, 1929. Serial No. 408,966.

This invention relates to a process of treating oils, and moreparticularly to a process of treating lubricating oil or cylinder stockfractions with decolorizing agents, such as fullers earth, various acidtreated clays, e. g. Filtrol, etc.

One object of the invention is to treat lubricating oil and cylinderstock fractions in the liquid phase directly as they are obtained in thedistillation and without first cooling thesestocks to atmospherictemperature, with decolorizi'ng clay and to effect considerable savingby eliminating cooling and reheating steps between the distillation andthe actual treating processes.

Another object is to decolorize lubricating oils and cylinder stockswithoutsubjecting them to a prior acid treatment.

Other objects and advantages of my process will be obvious in the courseof the following specification, read in conjunction with the drawing inwhich the single figure is a vertical elevation partly in sectionrepresenting one of the methods of carrying out my process. 7 7 In thefinishing of lubricating oils it has been common practice to cool andremove the lubricating distillate from the distillation equipment andfinish this oil either by acid treating and neutralizing, or by acidtreating and contacting with clay. In the present invention thelubricating oil distillate or-cylinder stock is cut to properspecification in the crude distillation equipment, for example, in apipe still run either under atmospheric rpressure or under" vacuum. Thedesired lubricating stream may be either a bottoms cut from one of thefractionating towers or may be a side stream in case there is only onetower. The hot lubricating distillate is then passed to a treater inwhich it is thoroughly mixed with finely divided clay. The oil and claymixture is removed, after the proper length of treating time, from thetreater .and is subjected to filtration and'cooling. The exact treatingtime can be best determined by experiment, and it may be stated in ageneral way that its order of magnitude is usually not mor'e'than a fewminutes. The filtration process may;

be carried out either before or after the coolmg.

Fine fullers earth, activatedclay such as German G. B., Filtrol, etc.may be used depending upon the desired quality of finished oil. Acidtreated clays containing both acid and water may also be used as will bedescribed later inmore detail.

The temperature of treating will depend on the stock to be treated andalso on the desired quality of the finished product. No

general rule can, therefore, be given since the best treatingtemperature will be determined by actual experiments in each case.However, it may be stated in a general way that the treating temperaturewill not be very different from the temperature at which the stock to betreated is obtained in the dis tillation process. This temperature will,therefore, be somewhere in the neighborhood of 350-500 F., and in nocase will it be lower than about 220250 F., or higher than thetemperature .at which substantial cracking takes place during thetreating time.

It becomes apparent from the foregoing description of the process thatmy invention eliminates the necessity of cooling the lubricatingdistillate and heatingit again to the proper treating temperature andalso the acid treatment required in conjunction with ordinary claytreating processes.

The drawing is a diagrammatic side elevation of apparatus suitable forcarrying out the process. The apparatus will be described in conjunctionwith the method of operating the same.

Numeral I designates a storage tank for the raw material which may bereduced crude or a similar oil stock. The stock is pumped.

maybe obtained as bottoms, cylinder stock,

or lubricating stocks may be obtained as side streams, and gas oil asoverhead distillate from the tower. The overhead distillate may becooled in cooler 5 and discharged into container 6 connected to a vacuumpump 7 by which the required vacuum is maintained on the apparatus. Thecondensed gas oil is discharged from container 6 into a storage tank(not shown). Several side streams may be taken from the tower. Two pans,8 and 9, are shown by way of illustration. Pan 8 yields a cylinder stockwhich is subjected to treating according to the present invention. Itwill be understood that when the several side streams are desirablelubricating oil fractions they may all be subjected, either separatelyor after uniting some of the streams, to my treating process.Furthermore, the distillation may be carried out under atmospheric orany suitable pressure.

"The stock to be treated, such as cylinder stock in the caseillustrated, is pumped through temperature control means 10 into thetreater 11 where it is contacted with the clay. The temperature controlmeans consists usually of a cooler in which the hot stock is cooledsomewhat to bring its temperature to the optimum treating temperature.It will be only very seldom necessary to heat the stock instead ofcooling in the temperature control means. The oil and clay mixture ispumped from the bottom of the treater through the cooler 12 to thefilter press 13 in which the clay is retained allowing the filtered andtreated oil to be discharged into the storage tank 14. The position ofthe filter press and cooler may be reversed or two coolers may beemployed one before and one after the filter press in which case thefirst cooler serves only as a partial cooler and the final cooling isobtained in the second cooler.

The treater is provided with an agitator 15 and a hopper 16 into whichthe clay may be dumped and forwarded by means of screw conveyor 17. Amotor 18 provides the necessary driving force for the treater and screwconveyor. 7

An alternate arrangement is also shown in which the clay is not chargedin a dry state to the treater but is first thoroughly admixed with acomparatively small quantity of an oil having approximately the samecharacteristics as the oil to be treated. This second method has theadvantage that an acid treated clay may be employed which has been onlypartially washed from the treating acid and contains both acid andwater. Such a clay'may be admixed with oil in a vessel 19 provided witha heating jacket and an agitator 20. The oil and wet clay mixture isthoroughly agitated and heated to a temperature high enough to removethe major part of the water after which the slurry is pumped throughline 21 into the treater 15,which may be provided with a vent pipe 22 toallow the escape of steam.

If a paraffin distillate is obtained as one of the cuts, it is passedthrough the temperature control means 10, treater 11 and filter press 13to remove the clay from the oil. The oil thus treated and freed from theclay is then passed through a cooler 23, chiller 24, I

Table 1 Cylinder stock Original Treated oil Lbs. clay (Filtrol) per gal.oil 1 1 2 Treating temp., F 500 500 500 500 Treating time in minutes 5 510 5 Gravity, A. P. I 20.7 2110 21.1 21.2 Flas F 545 545 550 545Viscosity 210F., seconds. 148 147 146 146 Pour, "F 105 100 110 Color onthe Tagliabue-Robinson calorimeter (dark glass) 1 1% 1% 1% Color hold(color after 10 hours at Table 2 Lubricating oil Treated oil Pallcx D DDecolorizmg agent Filtrol (75% Solids) Lbs. clay per gal. oil Treatingtemp., F 450 450 550 350 Treating time in minutes... 5 10 10 10 Gravity,A. P. 26.3 26. 9 26.8 26. 4 Flash, "F 500 515 515 520 Viscosity T.seconds 878 799 904 925 Viscosity 210 I seconds 76 75 75 75 Pour, F 2065 65 4.0 Color on the Tagliabue-Robinson colorimeter (dark glass) 8% 98% 8% Color hold (color after 16 hrs. at

It is evident from the above tables that both the color and the colorstability depend largely on the selection of the right treatingconditions especially the treating temperature, the treating time, andthe amount of clay used. In general, cylinder stocks are more improvedat higher and lubricating oil stocks at lower treating temperatures. Itseems that the optimum treating temperature for lubricating stocks issomewhere in the neighborhood of 450 F.

In the following claims the term lubricating oil is meant to designateboth lubrieating oils proper and cylinderoils.

Having thus described my process and the method of carrying it out whatI claim 1s:

1. Process of treating lubricating oil comprising passing an oil stockcontaining lubrieating oil through a narrow heated passageway into anenlarged fractionation zone to obtain a fraction consisting of thelubricating oil, removing the fraction from the frac tionation zone anddirectly agitating it in an unheated treating zone with a solidabsorbent decolorizing agent at a temperature not less than 220 F., andseparating the frac tion from the decolorizing agent.

2. Process of treating lubricating oil comprising passing an oil stockcontaining lubricating oil through a narrow heated passageway into anenlarged fractionation zone to obtain a fraction consisting of thelubricating oil, removing the fraction from the fractionation zone,passing the removed fraction through a temperature controlling zone,directly agitating it in an unheated treating zone with a solidabsorbent decolorizing agent at a temperature not less than 220 F., andseparating the fraction from the decolorizing agent.

3. The process according to claim 1 in which a temperature of from 350F. to 500 F. is maintained in the treating zone.

4:. The process according to claim 1 in which the fraction agitated withthe deco-lorizing agent consists of alubricating oil proper and thetreating temperature is maintained in the neighborhood of 450 F.

5. Process of treating lubricating oil, comprising passing an oil stockcontaining said lubricating oil through a narrow heated passageway intoan enlarged fractionation zone to obtain a fraction consisting of saidlubrieating oil, removing the fraction from the fractionation zone andpassing the removed fraction through a cooling zone in which itstemperature is reduced to a temperature of not less than 220 F.,directly agitating the cooled fraction in an unheated treating zone witha solid absorbent decolorizing agent, and separating said fraction fromthe decolorizing agent.

ALFRED A. WELLS.

